1设X服从3 10上的均匀分布计算PX≤4PX8; ∈已知PX a=04求A2设X服从正态分布N29计算PX ≤1P X 5;∈己知PX a=09求A用matlab求解

(1) syms x; % 定义随机变量X的概率密度函数 f = piecewise(x>=3 & x<=10, 1/7, x<3 | x>10, 0); % 计算P(X<=4) P1 = int(f, x, -Inf, 4); % 计算P(X>8) P2 = int(f, x, 8, Inf); % 解方程P(X>a)=0.4 a = solve(int(f, x, a, Inf) == 0.4, a);

(2) syms x; % 定义随机变量X的概率密度函数 f = 1/(3sqrt(2pi)) * exp(-(x-2)^2 / (2*9)); % 计算P(|X|<=1) P1 = int(f, x, -1, 1); % 计算P(|X|>5) P2 = int(f, x, -Inf, 2-5) + int(f, x, 2+5, Inf); % 解方程P(X<a)=0.9 a = solve(int(f, x, -Inf, a) == 0.9, a);